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Biomedical subjects

E Paoletti

Publications and source records attributed to E Paoletti.

At least 145 records · Page 8Linked to original sources
PubMed1988

Immune response to vaccinia virus and recombinant virus products in dogs.

A study was undertaken to determine the safety and suitability of vaccinia virus as an eukaryotic expression vector in dogs. Clinical signs were not seen in inoculated dogs, with the exception of small nodules at the site of inoculation. Vaccinia virus did not spread from dogs that were inoculated by SC (n = 5), intradermal (ID; n = 13), or intranasal (n = 3) routes to noninoculated dogs maintained in close contact. Replication of vaccinia virus appeared to be restricted in dogs because greater than or equal to 10(5) plaque-forming units of virus were required to induce an immune response by ID inoculation. Results were better with ID inoculation than with SC or intranasal inoculations. Repeated inoculations enhanced serum antibody titers, and annual reinoculation resulted in boosting of antibody titers. Maternal antibody interfered with virus replication and antibody production. Recombinant virus products induced antibody formation in dogs to human influenza-A virus, herpes simplex virus, and human hepatitis-B virus antigens. It was concluded that vaccinia virus would be safe and suitable as an eukaryotic expression vector in dogs.

Administration, Intranasal↗
PubMed1988

Pox viruses as eukaryotic cloning and expression vectors: future medical and veterinary vaccines.

It was proposed at the beginning of this article that the use of poxviruses as expression vectors provided a means of optimizing the conditions and prerequisites of vaccination and of elucidating a number of the associated problems. These advantages will now be summarized. Vaccinia virus recombinants carrying one or more multiple foreign genes have been shown to induce a sufficient immune response to that antigen in laboratory animals to protect against subsequent challenge by the infectious agent. In those animals tested the duration of immunity has been long-lasting with no apparent detrimental side-effects. Vaccinia virus is very stable in normal environmental situations and no cold-chain is required in the distribution network. There is no evidence for genetic instability of the vaccinia 'carrier' strain nor of loss of the inserted genetic elements. The vaccine is administered intradermally and it is proposed that one inoculation will be sufficient to induce immunity to multiple disease antigens; however, re-inoculation at a later time with the same or new antigenic determinants is not precluded. The efficiency of vaccinia virus as the vaccine strain used to eliminate the disease of smallpox with minimal side-effects is well documented. The recent studies described here on the development of vaccinia as a viral vector confer other advantages. Since the expression of the inserted genetic element is under vaccinia virus control, different levels of expression can be engineered by substituting the promoter sequence placed proximal to the insert. This leads to the possibility of high levels of expression when required for a single antigen or more modulated levels when multiple foreign antigens are expressed and 'genetic overload' could become a problem. Much work remains to be done on the body's immune response to this proposed genetic intrusion. The ability to insert large amounts of genetic information without disrupting virus replication and assembly indicates a great degree of flexibility in the genome strategy of the virus. This may indicate that the replication system can be further disrupted to eliminate or modify those sequences coding for virulence and wide host range to make the poxvirus vector as safe as possible for vaccine use. One of the reasons traditional vaccine strategy has failed for some virus groups is the degree of variability found in virus strains in nature. Influenza viruses are a good example, as are the bluetongue virus group, rotaviruses and bunyaviruses.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Effect of amino acid ingestion on blood amino acid profile in patients with chronic renal failure.

Arterial whole blood levels of amino acids (AA) were determined in patients with chronic renal failure (CRF) and in healthy volunteers before and for 75 min after the ingestion of an AA mixture simulating the AA content of an animal-protein meal. In CRF patients, total AA increased more than in control subjects as a consequence of an exaggerated rise in nonessential AA (+86%), mainly glutamine, proline, glutamate, serine, glycine, and alanine. Total essential AA in patients increased as much as in control subjects; however, threonine and phenylalanine showed greater increases while leucine had a smaller increase. As a consequence of the observed alterations, a striking unbalance in the postprandial pattern of arterial AA ensued in CRF patients. The flow of AA to all the organs is altered during the absorptive phase, which is crucial for body nitrogen-pool replenishment.

Adult↗
PubMed1987

Protection of guinea pigs from primary and recurrent herpes simplex virus (HSV) type 2 cutaneous disease with vaccinia virus recombinants expressing HSV glycoprotein D.

Vaccinia virus recombinants containing herpes simplex virus (HSV) type 1 (VP176) or type 2 (VP221) glycoprotein D (gD) genes were studied for their protective potential in the guinea pig model of recurrent HSV type 2 disease. Cells infected with these recombinants synthesized at least one protein (precursor, mature form, or both) that was precipitated with monoclonal antibody to HSV type-common determinants on gD. These determinants were detected on the surface of cells infected with the recombinants at 2 hr after infection. VP176 immunization protected against primary (P much less than .001) and recurrent (P much less than .001) cutaneous HSV type 2 lesions and ganglionic latency (62% protection). VP221 immunization protected against recurrent disease (P less than .05), although HSV type 2 ganglionic infection was established. Protection, first observed at two weeks after immunization, apparently did not involve HSV-specific neutralizing antibody because seroconversion was detected at 35-45 days after immunization. Protection was correlated with HSV-specific lymphoproliferation and the elaboration of lymphokines that enhance natural killer cell cytolysis.

Animals↗
PubMed1986

Insertion and deletion mutants of vaccinia virus.

Thirteen viable insertion mutants of vaccinia virus have been constructed. These mutants, containing coding sequences of the herpes simplex virus thymidine kinase (HSV-TK) gene, were generated by marker transfer via in vivo recombination. The mutants were identified using a replica filter plating technique by in situ hybridization using 32P-nick translated HSV-TK sequences and obtained as pure cultures by repeated plaque purification. Some of these insertion mutants were in turn used as substrates to generate viable deletion mutants of vaccinia virus in the presence of 5'-bromodeoxyuridine. An example of this approach resulting in a vaccinia virus deleted of approximately 1.5 kb of nonessential DNA is presented. Furthermore, the analysis of spontaneously occurring viable deletion mutants of vaccinia lacking approximately 21.4 kb of nonessential DNA is described.

Animals↗
PubMed1986

Vaccinia virus rifampicin-resistance locus specifies a late 63,000 Da gene product.

The genetic locus specifying rifampicin-resistance (RifR) in a vaccinia virus mutant has been localized by marker rescue analysis (J. Tartaglia and E. Paoletti (1985) Virology 147, 394-404). The mutation was defined by DNA sequence analysis as an AT to GC transition occurring 56 bp to the left of the unique XhoI site within HindIII D. The point mutation resulted in an asparagine to aspartic acid substitution 60 amino acids from the predicted C-terminus. Specific DNA probes were used to characterize the RifR designated gene at the transcriptional and translational levels. This region is transcriptionally active only after vaccinia virus DNA synthesis, but not in the presence of cytosine arabinoside suggesting that the RifR function is a late gene product. Translation of hybrid selected RNA to DNA surrounding the mutant marker directed the synthesis of a polypeptide with an apparent mol wt of 63 kDa. Transcriptional and translational mapping studies showed that the mRNA encoding this 63-kDa polypeptide was initiated approximately 460 bp to the right of the HindIII D-A junction and was transcribed in a leftward direction into the HindIII D region.

Chromosome Mapping↗
PubMed1986

Response of dairy calves to vaccinia viruses that express foreign genes.

Repeated intradermal inoculations of calves with wild-type vaccinia virus and recombinant vaccinia viruses expressing human hepatitis B virus surface antigen and herpes simplex virus, type 1, glycoprotein D produced characteristic pox lesions at each site of injection. In some instances, calves were inoculated as many as five times at intervals from 4 to 7 weeks. The lesions invariably were more severe after the second inoculation. Subsequent inoculations produced a less severe area of redness, swelling, necrosis, and scab formation. No other signs of illness, such as an elevation in temperature, were noted in the calves. Vaccinia virus was isolated in low titers from scabs taken at various times after inoculation. No lesions were formed at the sites injected with tissue culture fluid and cellular debris at the same time that virus inoculations were made. Calf contact controls remained normal through the 8-week exposure in isolation units with calves inoculated twice with vaccinia virus. No neutralizing antibody to vaccinia virus was detected in the contact controls. In contrast, the virus-inoculated calves developed neutralizing antibody to vaccinia virus and to herpes simplex virus glycoprotein D in serum. In all cattle, a second inoculation significantly enhanced the neutralizing antibody response within 1 week, suggesting that an anamnestic response had occurred. No antibody to hepatitis B virus surface antigen was elicited in calves after repeated inoculations with vaccinia recombinants that express hepatitis B virus surface antigen and are known to elicit in rabbits antibodies reactive with hepatitis B virus surface antigen.

Animals↗
PubMed1985

Recombinant vaccinia virus: immunization against multiple pathogens.

The coding sequences for the hepatitis B virus surface antigen, the herpes simplex virus glycoprotein D, and the influenza virus hemagglutinin were inserted into a single vaccinia virus genome. Rabbits inoculated intravenously or intradermally with this polyvalent vaccinia virus recombinant produced antibodies reactive to all three authentic foreign antigens. In addition, the feasibility of multiple rounds of vaccination with recombinant vaccinia virus was demonstrated.

Animals↗
PubMed1985

Physical mapping and DNA sequence analysis of the rifampicin resistance locus in vaccinia virus.

Rifampicin has been shown to inhibit the maturation of poxviruses at a discrete step in envelope formation (Moss et al., 1969; Pennington et al., 1970; Nagayama et al., 1970; Grimley et al., 1970). A rifampicin-resistant vaccinia virus mutant (RifR) was selected for its ability to grow in the presence of 100 micrograms/ml of rifampicin. Utilizing intact DNA or endonuclease restricted cloned DNA subfragments derived from the RifR mutant virus, the locus specifying rifampicin resistance was physically mapped by marker rescue analysis leftward of the unique XhoI site within the HindIII D fragment. DNA sequencing of a 445 bp fragment encompassing this region revealed an AT to GC transition when compared with the equivalent wild-type DNA fragment. Analysis of the six potential open reading frames within the 445-bp fragment indicated only one available open reading frame. On this basis, the rifampicin-resistant vaccinia virus mutant was shown to have a codon transition from asparagine to aspartic acid.

Amino Acid Sequence↗